Method and Algorithm of Fault Detecting in Circuits of the Thyristor Excitation System of Synchronous Machines

In this study the algorithm of detection of faults in a converter bridge of thyristor excitation system is considered, based on control of phase currents before a thyristor bridge and control of rectified rotor current. For fault identification following fault features are distinguished from controlled currents and used: phase disruption, increasing of duration of phase current flow in the controlled direction, increasing of phase currents and bridge current above pickup values (set points) and control of free components in phase currents. Suggested method and designed protection of excitation system with static thyristor rectifier circuits algorithm allows detecting the breakdown and the fault of a thyristor (group of thyristors), and a short circuit at the bridge poles.